Influence of Substrate Surface Condition on the Cold Spray Deposition Behavior

Cold spray technique has the advantages over the conventional thermal spray technique, accordingly it is expected that the alternative technique of thermal spray. However, the deposition mechanism has not been completely understood. Our recent work showed that nascent surface creation is the important factor of the cold spray deposition, which occurred in high-velocity impingement of the particle. After the plastic deformation of the particles and substrate, the native oxide breaks; subsequently, a nascent surface can be created and direct contact initiates deposition. Therefore, the native oxide condition is expected to have influence on the nascent surface creation behavior, consequently cold spray deposition. In this study, in order to understand the influence of substrate surface oxide conditions on cold spray deposition, several different heat-treated substrates are prepared. Those have different thick oxide film on the surface. Particles were sparsely deposited on its; these specimen were prepared by using a small powder feed rate and high traverse speed. From the investigation of the deposition efficiency such as that evaluated by the deposit particle number, the thicker oxide film substrate has a lower deposition efficiency. The substrate surface oxide condition has a strong influence on the deposition behavior.